1. Field of the Invention
The present invention concerns a method and a device for coating an inner surface of a pipe. The method includes a step of forming a layer at a curved portion of the pipe, the layer being constituted by an adhesive agent or a lining material and by a reinforcing material transported by means of gas flowing inside the pipe.
2. Description of the Prior Art
According to a conventional method for coating an inner surface of a pipe, an adhesive agent or a lining material is stuck to the whole pipe to be treated and then a reinforcing material is also caused to adhere to the whole adhesive agent or the whole lining material.
However, because of reasons as specifically set forth hereinafter, there often are occasions when the adhesion of the reinforcing material is especially needed at a curved portion of a pipe.
(a) In a piping to be treated, straight portions are hardly or not at all damaged by fluid transportation whereas curved portions are more subjected to damages because the same are violently crashed against the transported fluid.
(b) Since the inner surface of pipe is generally lined by means of gas-flow transportation of lining material, although lining may be formed with a sufficient thickness at the straight pipe portions, formed lining tends to be undesirably thin at the curved pipe portions because the lining material is often forced by the gas flow to pass therethrough.
If the conventional method is applied in the above cases, unnecessary adhesion of the reinforcing fiber often leads to pressure loss in the piping, and further especially in the case of a long piping necessary amount of reinforcing fiber increases whereby the whole treatment takes considerable time and labor.
Also, in the conventional method, the sticking operation of the reinforcing material to the adhesive agent or to the lining material has been carried out in such a way that a lining material having a viscosity of about 5000 cps is fed into the piping at a supply rate approximately 100 to 200 cc/m and at the same time pressured gas is fed into the piping at about 40 m/sec to cause a gas-liquid mixture flow to flow along the piping thereby the lining material coating the inner surface of the piping.
This method, however, provides maximum treatment speed up only to 0.5 to 3 m/min; thus, the treatment of a long piping takes considerably long time. Further, with this method, since it is difficult to treat main pipes and branch pipes at the same time, the lining operation need be carried out for each main pipe and branch pipe separately, whereby operation efficiency is extremely low.
A conventional device employed for the above operation comprises a reinforcing material supplying apparatus including a supply tank for depositing the reinforcing material, reinforcing material dispersion means for dispersing the reinforcing material supplied from the tank into gas, a mixing section for mixing gas from a blower with the reinforcing material mixed gas from the reinforcing material dispersion means and a supply passage for feeding the mixed gas from the mixing section into a piping to be treated, the reinforcing material dispersion means being constituted by an auxiliary dispersion tank and a dispersion tank serially with respect to each other for dispersing the reinforcing material into the gas in a suction passage of an ejector provided as the mixing section (Japanese Utility Model Application No. 60-97221).
However, in both the auxiliary dispersion tank and the dispersion tank, since the reinforcing material is dispersed by means of stirring effect of the suction gas of the ejector, the gas flow speed is not sufficiently high. Thus, there has been room for improvement in the dispersion efficiency.